Potentiometer



Jan. 12 1926.

1,569,042 D. H. sHERlFF, .1R

POTENTIOMETER Filed March 5, 1925 2 Sheets-Sheet l IlllllllllllllIlllllllllllllllii' Jan. 12 1926. 1,569,042

D. H. SHERIFF, JR Y POTENTIOMETER Filed March 5, 1925 2 sheets-sheet 2 Patented Jan. 12, 1926.

UNITED STATES PATENT OFFICE.

'.POTENTIOMETER.

Application led March 5, 1923. Serial No. 622,936.

To all fwzomr it may concern:

SHERIFF, J r., a citizen'of the United States, residing at Kansas City, in thecounty of Jackson and State of Missouri, have invented certain new and useful Improvements in Potentiometer-s, of which the following is a specification.

My invention relates to certain new and useful improvements in potentiometers and it primarily has for its objects to provide such an instrument by the use of which a plurality of circuits may be cont-rolled from one unit, and to provide such an instrument in which the condensers for the several circuits are contained o1` embodied in theinstrument itself, thus making a single unit of the condenser andn potentiometer proper.

In its more specific nature the invention further resides in those novel details of construction, combination and arrangement of parts, all of which will be first fully explained, then be specifically pointed out in the'appended claims, reference being had to the accompanying drawings in which:

Figure 1 is a rear elevation of one embodiment of the invention.

Figure 2 isa vertical cross section on the line 2 2 of Figure 1. Y f

Figure 3 is a vertical section on the line 3 3 of Figure 2 showing one condenser arrangement.

Figure 4 is a diagrammatic view of the circult arrangement of the `unt and showing the outside. circuit connections in dotted Figure 5 is a. diagrammatic view of a modified form of the invention showing the resistance units in several sections with the contact lingers, one cooperating with each resistance unit.

yIn the drawings, in which like numerals and letters of reference designate like parts in al1 the igures, 1 represents the base which is preferably made of vulcanite, vulcanized fiber, bakelite or other suitable insulating composition. The base ll is apertured at 2 to constitute a bearing for. the adjusting sleeves and the base is also provided. with a resistance unit 3. The unit 3 is preferably mounted on the back lof,the base and has ,circuit terminals connected to binding posts 4 and 5 with which the outside battery or source of E. M. F. 32 is adapted to be connected. A

rllhe adjusting sleeves or spindles comprise a central shaft 6 having a shoulder 7 and a finger piece 8 by which the spindle 6 may be turned. Mounted on the spindle 6 is a tubular spindle or sleeve 9 that turns loosely on the spindle 6 and is shouldered at 10 and is provided with aI finger piece 11 by which it may be turned.

Mounted on the sleeve or hollow spindle 9 is another hollow spindle or sleeve 12 having a shoulder 13 and finger piece 14, the spindle 12 having a collar 15 by which the spindle 12 is held from endwise movement in the bearing 2. The spindle 12 is held against endwise movement in t-he bearing 2 by the shoulder 13 and an insulating collar secured on the opposite end of the spindle 9, while the spindle 6 is similarly held by the shoulder 7 and insulating collar 16. Secured to the insulating collar 16 is a ring 17 carrying a `springy contact finger 18 which engages the resistance element 3.

21 is a ring'secured on the insulatin collar 2() and carrying a springy contact nger 22 to engage the resistance element 3; while 25 designates a ring secured on the insulating ring 24 on the spindle 12 and carrying a springy contact finger 26 to engage the resistance element 3.

28, 29 and 30 indicate binding posts or contact terminals to which the rings 17, 21 and 25 are respectively connected by iexible wires 19, 23 and 27. a

31 are/,stops-for the fingers 18, 22 and 26 at the extremities of their adjustable positions.

Embedded within or associated with the base 1 are condenser sets A, B, C, D, E and F respectively, one plate of each of the condenser sets A, F and E being connected to the terminal 4; one plate of each of the condenser sets B, C and D is connected to the terminal 5. The other plate of each of the condenser sets A and B is electrically connected tothe terminal 28, the other plate of each of the condenser sets C and F is connected with the terminal 29, While the other plate of each of the condenser sets D and C is connected with the terminal 30.

While the'arrangement of the condenser sets shown in Figure 3 is illustrated as one embodiment of my invention it is quite obvious that the arrangementmay be altered to suit the desire of the designer, the prin cipal feature being the association of the condenser with the potentiometer as a single unit to control one or more circuits.

In the practical use of the invention the frictional resistance of the springy contact lingers 18, 22 and 26 where they engage the coil 3 Will be sufficient to prevent their turnning unless their particularflnger pieces 8,

11 or 14 are turned.

The embodiment of the invention shown in Figures 1V to 4 inclusive is illustrative of an arrangement by which three circuits may be controlled from one and the same insulating unit. It will, of course, be obvious` that the number of circuit controls may be varied to suitthe desires of the designers and Within the limits of the practical size of the apparatus.

The external circuit connections have a common connection 33 with' the posts 4 in which connection the battery 32 is contained While the other circuit lines 34, 35 and 36 connect respectively to the binding posts 28, 29 and 30. y

From the foregoing it will be seen anyone of the three circuits may be adjusted simply 'by turning its respective knob 8, 11 or 14, or all of the circuits may be adjusted by turning the respective finger piece or knob as desired.

Instead of making the resistance unit 3 as a single unit withall of the springy contact lingers engaging the same, it may be made of separate subeunits 3a, 3b and 3 as indicated in Figure 5'and the springy contact fingers 18a, 22 and 26 may be correspondingly proportioned to engage the respective sub-units.;

This potentiometer is primarily intended to be used as a tuning device'of a radio device. The advantages of the device are greater economy smaller panel space required and 1n some in the material used,`

cases the reduced current consumption operation and advantages of the invention Will be clear to those skilled in the art.

lVhat I claim is:

1. A potentiometer comprising a base, a resistance element mounted on the base, a plurality of contact lingers9A mounted on the base to turn on a common axis, said lingers lying in different planes with their contacting ends bent to lie in the same' plane in engagement with said resistance element, those of the fingers overlying others having provision whereby they Will pass over the fingers beneath, each of the contact lingers being adapted for variation over portions of the resistance element also covered by other of thecontact lingers substantially as shown and described. a

2. In a multiple potentiometer, a base, a resistanceelement associated with the base, a plurality of concentric s indles With operating knobs and contact ngers, the latter engaging said resistance element, terminal posts to which the ends of said resistance element are connected, and terminal posts to Which said ngers are respectively connected.V

vDAVID HARRISON sHERIFF, JR. 

